1. Field of the Invention
The present invention relates to light insulated lamps, method of preparing such lamps and illuminating systems using such lamps therein. More specifically, the present invention is directed to encapsulating a base of a lamp with leads comprises two portions, a first portion inside an envelope and a second portion extends out from the base and at an angle of about 90.degree. to the first portion, utilizing an opaque plastic material, such as polybutylene terephthalate (PBT). The lamp with the encapsulated base, in combination with a compressive gasket and filter ring is then used to obtain an illuminating system having IR sealing at the backside of an instrument panel which does not affect night vision goggle operation.
More specific objects and advantages of the invention will hereinafter be made clear or become apparent to those skilled in the art during the course of explanation of preferred embodiments of the invention.
2. Description of the Prior Art
In different applications, it is imperative that illumination, particularly from incandescent lamps, be rigorously controlled. One such application is the utilization of night vision goggles by operators of aircraft. In almost all instances, the instrument panels of aircraft are illuminated by incandescent light which is transmitted through a plastic panel such as molded acrylic plastic. The panel is painted or otherwise coated with opaque material which is then removed from desired spots for transmission of information to the pilot, such as, for example, data, instructional material, frequencies and the like. To provide light in the desired frequency ranges, a filtering element may be utilized so that incandescent radiation of undesired frequencies is eliminated from the acrylic plastic.
It has been found to be a problem that radiation of undesirable frequencies can leak from the incandescent lamp through the backboard with lamps made in accordance with the prior art. Typically, prior art lamps consist of an incandescent lamp with a pair of leads extending therefrom. The leads are then soldered to appropriate .+-. busses on top of the circuit board to provide the desired electrical connection to illuminate the lamp. Irrespective of the attempt to place opaque which materials or the like on the backboard, the light nonetheless leaks through, providing undesirable incandescent radiation at frequencies that sometimes degrade night vision goggles performance.